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NAME
     vcosti - initialize the  array  xWSAVE,  which  is  used  in
     xCOST.

SYNOPSIS
     SUBROUTINE COSTI (N, RWSAVE)

     SUBROUTINE DCOSTI (N, DWSAVE)

     SUBROUTINE VCOSTI (N, RWSAVE)

     SUBROUTINE VDCOSTI (N, DWSAVE)



     #include <sunperf.h>

     void costi (int n, float *rwsave) ;

     void dcosti (int n, double *dwsave) ;

     void vcosti (int n, float *rwsave) ;

     void vdcosti (int n, float *dwsave) ;

ARGUMENTS
     N         Length of the sequence  to  be  transformed.   The
               method  is  most efficient when N - 1 is a product
               of small primes.  N >= 2.

     xWSAVE    On entry, an array with a dimension of at least (3
               *  N  + 15).  Different xWSAVE arrays are required
               for different values of  N.   This  initialization
               does  not  have  to  be  repeated between calls to
               xCOST as long as N and  xWSAVE  remain  unchanged,
               thus  subsequent transforms can be obtained faster
               than the first.

SAMPLE PROGRAM
           PROGRAM TEST
           IMPLICIT NONE
     C
           INTEGER         N
           PARAMETER      (N = 9)
     C
           INTEGER         I
           REAL            PI, X(N), WSAVE(3 * N + 15)
     C
           EXTERNAL        COST, COSTI
           INTRINSIC       ACOS, COS
     C
     C     Initialize the array X to an even sequence, that is, it can be
     C     expanded in terms of a trigonometric series that contains only
     C     cosine terms.
     C
           PI = ACOS (-1.0)
           DO 100, I=1, N
             X(I) = COS ((I - 1.0) * 2.0 * PI / (N - 1.0))
       100 CONTINUE
     C
           CALL COSTI (N, WSAVE)
           PRINT 1000
           PRINT 1010, (X(I), I = 1, N)
           CALL COST (N, X, WSAVE)
           PRINT 1020
           PRINT 1010, (X(I), I = 1, N)
           CALL COST (N, X, WSAVE)
           PRINT 1030
           PRINT 1010, (X(I), I = 1, N)
     C
      1000 FORMAT (1X, 'Original Sequence: ')
      1010 FORMAT (1X, 100(F5.1, 1X))
      1020 FORMAT (1X, 'Transformed Sequence: ')
      1030 FORMAT (1X, 'Recovered Sequence: ')
           END

SAMPLE OUTPUT
      Original Sequence:
        1.0   0.7   0.0  -0.7  -1.0  -0.7   0.0   0.7   1.0
      Transformed Sequence:
        0.0   0.0   8.0   0.0   0.0   0.0   0.0   0.0   0.0
      Recovered Sequence:
       16.0  11.3   0.0 -11.3 -16.0 -11.3   0.0  11.3  16.0

Партнёры:

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